Inheritance of maternal antibody concentration in the bovine neonate PublicDeposited

Descriptions

Serum samples were collected between 24 and 48 h of age
from 408 Hereford calves of a selection experiment and from 200
Angus, Hereford and Red Poll calves of another experimental
population (Germ Plasm Utilization project). Concentrations of
Immunoglobulin G₁ (IgG₁) were determined by single radial
immunodiffusion. Breed or selection line of calf and age of
dam were the most important factors influencing IgG₁
concentrations (P < .01). In the Germ Plasm Utilization (GPU)
herd, Angus calves were highest, Red Polls were intermediate
and Herefords were lowest in serum concentrations. Calves from
Hereford lines selected for weaning weight, yearling weight or
yearling weight and muscling score index were lower in IgG₁
concentration than calves from the randomly selected control
line. In both populations immunoglobulin levels in the calf
increased as age of dam increased. Calf sex did not affect
IgG₁ in either population. In Selection Experiment
Herefords, increased calving difficulty was associated with a decrease in calf IgG₁ levels (P < .05). In the GPU population,
as birth weight increased IgG₁ levels increased in the
Angus, did not change in the Red Polls and decreased in the
Herefords (P < .05).
Heritabilities of calf serum IgG₁ concentration, estimated
from paternal half-sib analysis on a within line or breed
basis, were .03 ±-09 and .13 ±.19 in the two populations. In
the Selection Experiment Herefords, when the component of
variance for selection line was added both to the numerator and
denominator of h² the revised estimate was .09 + .09. Heritabilities
of maternal effects on IgG₁ concentration were also
estimated (by nesting calves within maternal grandsires) on a
within line or breed basis. These heritabilities were .23 +
.17 and -.07 ± .27 for the Selection Experiment and GPU populations,
respectively. In the Selection Experiment population,
when the variance component for selection line was added to the
numerator and denominator of maternal effects heritability, the
estimate was .27 ± .17. Those calves that died had a lower
mean IgG₁ concentration than the overall population average
(P < .01).